User`s guide

32 • Operation Theorem
users must check if another IRQ is also asserted, then clear current IRQ
to allow the next IRQ occurring.
The two IRQs are named as INT1 and INT2. INT1 comes from AD EOC
or the FIFO half-full flag. INT2 comes from timer‘s pacer output or the
external interrupt request. The sources of INT1 and INT2 are selective by
the Interrupt Control (ISC) Register.
Because of dual interrupt system, for example, you can use FIFO half-full
and external interrupt at the same time if your software ISR can
distinguish these two events.
4.2.4 Interrupt Source Control
There are two bits to control the IRQ sources of INT1 and INT2. Refer to
section 3.10 for the details of the bits. In addition, the PCI controller itself
can also control the using of the interrupt. For manipulating the interrupt
system more easily, ADLINK recommend you to use the function
_9111_INT_Source_Control to control the IRQ source so that you can
disable one or two of the IRQ sources.
Note that even you disable all the two IRQ sources without change the
initial condition of the PCI controller, the PCI BIOS still assigns an IRQ
level to the PCI card and it will occupy the PC resource. It is not
suggested to re-design the initial condition of the PCI card by users‘ own
application software. If users want to disable the IRQ level, please use
the ADLINK’s software utility to change the power on interrupt setting.
4.3 Extended Digital I/O Port
There are 4 extended digital input (EDI) signals and 4 extended digital
output (EDO) signals on CN3 connector. The 4 EDI signals are dedicated
used as input signal, however the 4 EDO signals can be used as digital
input (Mode 1), digital output (Mode 2) or channel number output (Mode
3).
For power on safety, the EDO channel is set to be input when power on
initial. To modify the configuration of the usage of the signals, please use
the “_9111_Set_EDO_Function” in the library.
Note that w hen set the EDO function as channel number output (Mode 3),
it presents the high nibble (4 MSBs) of the channel number no matter
manual scan or auto scan mode.